Muffler with cup-shaped baffle



June 13, 1950 J. P. MARX 2,511,597

MUFFLER WITH CUP SHAPED BAFFLE Filed April 30, 1947 2 Sheets-Sheet 1 LT F i 1?: i i F i8 15' 5" f INVENTOR. JUSEPH/ HAFX ATTORNEY June 13, 1950 J, MARX 2,511,597

MUFFLER WITH CUP SHAPED BAFFLE Filed April 30, 1947 2 She ets-Sheet 2 IN VEN TOR. L/JSEPH F. HARX Patented June 13, 1950 UNITED STATES- MUFFLER (1TH CUP-SHAPEE BAFFLE Joseph PF. Marx, Hartford, Wis.

Appiication April 3%, 1947,,Serial No. 742 54.897

(Q1. Mil-#58 Claims.

The present invention relates to improvements in mufflers, and more particularly to an inexpensively constructed durable silence for exhaust gases and sound waves.

The mufiler or silencer of the present invention is partictularly constructed for use in connection with low velocity internal combustionengines, gas engines, air motors and the like. Certain known types of mufflers designed to silence the noise-s of an engine or motor exhaust embody various conventional types of. construction, such as, for example, the inclusion of an outer shell. and in some instances intermediate tubular passageways and chambers. Most mufflers embodying such features ofconstruction have at least some of the passageways therein coextensive with the entire length of the mufiler, which passageways are interconnected by perforations. provided to create a turbulence in the escaping. gasesand sound waves. Other known mufflers designed especially foruse on low velocity engines, such as the type of muffler shown and claimed in my Patent No. 2,416,452, dated February 25, 19%37, include a. casing or shell having a. perforate transverse partition disposed between perforated baffles.

It has. been definitely established that mufflers including coextensive axial passageways are unsuited for silencing the noises of the exhaust gases from a low velocity engine and that the flow of gases and sound waves along and through a perforated partition and baffles devoid of louvers or other structure designed to prevent free uninterrupted flow of the gases creates high frequency sounds or whistling. Such known types of mufflers are objectionable also from the standpoint of involved and costly assembly.

It is therefore an object of the invention to provide a durable low-cost muffler which is especially suited for silencing the noises of the ex haust gases from low velocity engines, and which is inexpensive to construct and may be installed easily and quickly and, embodies a minimum of parts;

Another object is to. provide a muffler with a series of compartments of different capacitiesinterconnected through a plurality Of louvered perforations.

, Another object is to provide a. muffler of the character described withone or more domed baffles having openings therein internally louvered so as to afford means to effectively reduce the noises of gases and sound waves passing therethrough.

Another object of the invention is to provide a-low velocity mufiler of a kind which causes the gases and sound waves entering therein to be divided into a multiplicity of turbulent non-directional streams of different values, lengths and velocities so as to absorb and destroy sound waves of all: frequencies and provide maximum efficiency in silencing noises.

Another object is to provide amufller organization embodying-novel features of construction.

Other and further objects of the present in.- ventionwill' be apparent from the following description and claims: and are illustrated in the accompanying drawings which by way of illustration' show preferred embodiments and the principlesthereof; Other'emhodiments of the in-. vention embodying the same principle may be used and structural: changes may be. made as desired by. those skilled in the art without departing from the present invention or the purview of the appended claims.

In thedrawings:

Fig. I is 'a longitudinal central-sectional. view of a muiller embodying" features of the present-invention.

Fig; 2' is a longitudinal central. sectional view of the muffler embodying other features of the invention.

Fig. 3 is a longitudinal central sectional view of a muffler substantially like those' shown in. Figs. 1 and 2; but embodying other features ofthe invention.

Fig. 4 is a longitudinal central sectional view of a muffler having-a singlerbaffle therein.

Fig. 5 is a transverse sectional view taken, for convenience, substantially on a line E-5.of' Fig. 4.

Fig. 6. is a longitudinal central sectional view of another form of" mufller.

Fig. '7 is a-transverse secti'onal view of a. muffler, substantially like Fig. 5, but showing a modified form of louver.

Fig. 8 is: an enlarged fragmentary sectional detail view taken substantially on line 88 of Fig. 7.

Fig. 9 is a fragmentary sectional detail view, substantially like :Fig. 8, but showing a modified form of louver.

Fig. 10 is a transverse sectional View of a muffler showing another modified form of louver therein.

The silencers embodying the features of the present invention and disclosed in the accompanying drawings are formed of sheet material such as sheet steel or metal tubing and are constructed of a plurality of separate parts all joined, as by welding, into an integral self-contained unit having a uniform external appearance.

Referring particularly to the silencer illustrated in Fig. 1, the muffler includes a cylindrical shell generally indicated at H, preferably formed from two cylindrical end portions l2 and a cylindrical intermediate portion 13. Each of the end portions lZis fashioned in a substantially cup-like configuration having a cylindrical wall portion 14 and an end wall IS. The end'wall is suitably apertured and the aperture is provided with an internally directed annular flange 16. The

flanged aperture in one end portion receives a tubular fitting II to adapt the mufiier for ready attachment to the exhaust of a motor. The flanged aperture in the other end portion I2 receives a tail fitting I8. The fittings l1 and I8 may be secured in the respective flanged openings by any suitable means, it being preferred however, that the fittings and the flanges I6 be joined as by welding at I9. The cylindrical wall portion I4 of each of the end portions I2 is provided on its free circumferential edge with an outwardly turned circumferential flange 29, adapted to receive in abutment therewith an annular flange 2| one of which is provided on each end of the intermediate cylindrical wall portion I I. When the unit is assembled the circumferential flanges 29 are suitably rolled over the annular flanges 2| so as to afford a tight joining of the related members and further to provide external circumferential ribs to reinforce the assembly.

Prior to joining the end portions I2 with the intermediate portion, a dome-shaped baffle, generally indicated at 22, is arranged in place between the opposed flanges of the related portions and is secured in such position when the circumferential flange 2|] is rolled over in the manner described hereinabove. Each of the two baflles 22 shown in the embodiment disclosed in Fig. 1 includes a cylindrical wall portion 23 having an end wall 24 closing one end thereof and an external circumferential flange 25 at the other end thereof. The cylindrical wall portion 23 of the baflle is concentric with the wall of the shell II and is spaced therefrom in the manner illustrated. A plurality of elongated perforations 26 are provided in the cylindrical baflle wall 23, said perforations extending longitudinally thereof and being spaced apart'circumferentially suitable distances so as to dispose the perforations in closely spaced pairs. Upon referring to Fig. 5, (described as taken on Fig. 4 but which also represents the structures of Figs. 1, 2 and 3) it will be noted that each of the perforations 26 is provided with an angularly disposed internal louver 21, which louvers are struck out of the body of the cylindrical wall and have their ends and one longitudinal edge thereof integral with said wall. It should be quite apparent at this time that the effective opening at each of the perforations 26 is determined by the distance to which the louver 21 is arched inwardly. Consequently it is a simple matter to determine the size of the opening so as to adapt the muflier for use in association with engines having different exhaust velocities.

Referring again to the disclosure in Fig. 1 it will be observed that both of the domed baffles 22 are disposed in a common direction. That is, the cylindrical body portion 23 of each is disposed towards the outlet end of the muffler. In operation exhaust gases and sound waves entering the shell through the fitting I'I flow into a chamber 28 defined by the cylindrical end portion I2 and the bailie adjacent thereto. The gases and sound waves then pass through the perforations 26 in said baflie outwardly radially in a tangential direction, and because the louvers are arranged in pairs and are opposed one to the other, the gases flowing therethrough are turbulated sumciently to break up the streams and disrupt the sound waves and frequencies contained therein. Upon leaving the louvered perforations 26 the gases flow freely in and about the intermediate chamber 29 defined in part by the intermediate shell portion I3. This chamber has a capacity exceeding all) the capacity of the chamber 28 and consequently said gases expand sufficiently to further disrupt the sound waves and frequencies. As the gases continue their passage through the mufiier they pass out of the chamber 29 through the louvered perforations 26 in the next baiiie 22 and into an end chamber 3| defined by said baffle and the cupshaped end portion I2. Inasmuch as the chamber 3| has a capacity considerably less than the capacity of the chamber 29 the gases are compressed or restrained sufiiciently to again disturb and disrupt the sound waves and frequencies to thereby eliminate or deaden all noises in the gases passing out of the tail fitting I9.

The muiller construction shown in Fig. 2 is substantially like that disclosed in Fig. 1 and like numerals are used to identify corresponding parts. As illustrated, the dome-shaped baffles 22 are disposed in opposed directions so as to provideend chambers 28 and 3| having less capacity than the intermediate chamber 29. The function of a mufiier constructed in this manner is substantially like that of a muffler previously described in that the sound waves and gases en, tering the small chamber 26 flow into the large chamber 29 through the radial louvered perforations 26 in the cylindrical wall 23 of the first baflie. The expanded gases and sound waves leaving the chamber 29 flow through the louvered perforations 26 in the second bafiie 22 and are contracted or compressed upon entering the end chamber 3| from where they pass out through the tail-fitting I8. The muflier disclosed in Fig. 3 differs from the construction of the mufliers previously described in that dome-shaped baffles 22 are opposed to each other in such manner that relatively large end chambers 28--3| are provided and a restricted intermediate chamber 29 is formed. The operation and function of this mufiler is substantially like that of the previously described muillers in that the gases and sound waves are expanded and restricted during passage, and like numbers are used to identify corresponding parts thereof.

Fig. 4 shows a silencer having but one domeshaped baflie 22 therein. The baffle 22 is like the baflies employed in the previously described constructions and its circumferential flange 25 is firmly embedded in the reinforcing bead 2i! joining the two end portions I2 of the muifler together. This assembly is such that gases entering chamber 32 flow through the radially disposed louvered apertures 26 into chamber 33, which has a smaller capacity than the chamber 32 and consequently the turbulated gases are contracted or compressed slightly, thus causing the sound waves to be on of phase one with the other. Fig. 6 shows a muliler constructed substantially like that shown in Fig. 4 except in this instance the outer shell thereof is fashioned from a shallow cup-shaped end portion 34 joined in a rein'= forcing bed 20 to a second cup-shaped portion 35. The cup-shaped portion 34 is provided with an inlet fitting II which is suitably joined as by welding I9 to an internal flange I6. The other end portion 35 has its end wall 36 provided with a plurality of ports 31 through which sound deadened exhaust gases pass. In other respects this construction functions like the structures previously described, the gases and sound waves passing through the radial louvered perforations 26 and expanding into the exhaust chamber 38.

Figs. '7 and 8 show a modified form of construction for the dome-shaped baiiie. As shown,

1 the cylindrical wall 23a of the baffle 22a is provided with a plurality of circumferentially spaced apart slits 4! to define elongated portions ii? which are struck inwardly from the plane of the cylindrical wall 23a to define louvers joined to said wall at their ends only. Gases and sound waves flowing through the openings 13, provided by striking said louvers inwardly, iiow in a circumferential direction and are turbulated in such manner as to break up all sound wave frequencies in the gases flowing th rethrough.

Fig. 9 teaches a modified form of construction of a louver subs tantially like that shown in Figs. '7 and 8. As illustrated, the inwardly struck portion 42a is connected to the cylindrical wall of the dome-shaped baiile at one end only, thus affording a passageway for the gases and sound waves along three of its sides.

The muli'ier structure illustrated in Fig. 19 differs from that shown in Fig. 5 only in that all of the inwardly struck louvers 2M are disposed in a common direction circumferentially.

It should be understood that although a plurality of differently assembled silencers have be n illustrated in the accompanying drc rings described in detail herein, the construction each is such as to afford progressive expsion or contraction of the exhaust gases as the pass through the muffler and that means is provided in each whereby the direction of flow of said gases is interrupted to such degree as to break up all sound wave frequencies and effectively eliminate and deaden all sounds of the exhaust. It should be understood further that any one of the muf fiers disclosed herein may incorporate louvers constructed in accordance with any one of the several teachings herein, and that the invention is not to be limited to the specific form of lou illustrated in each disclosure, and that other modifications of detail structure may be embodied therein without departing from the spirit of the invention or the scope of the appended claims.

I claim:

1. A muffler comprising a cylindrical casing having inlet and outlet openings for exhaust gases, an imperforate partition dividing said casing into compartments, a dome in said partition including a wall portion concentric with the horizontal casing, said dome having an imperiorate end wall, and a plurality of circumferentially disposed louvered perforations in said concentric wall portion, said louvered perforations being arranged in pairs and the louvers on each pair being integral with one longitudinal edge of the wall portion and disposed angularly away from each other inwardly to define opposed tan-- gential openings to create a turbulence in the gases passing through the perforations.

2. A mufiler comprising a shell having inlet and outlet openings in its ends through which gases and sound waves may pass while entering and leaving said shell, a domed partition in and secured at its base only to said shell including a cylindrical wall portion spaced from the wall of the shell, and louvers in the cylindrical wall in the form of arches formed by deflecting portions of said wall inwardly, said louvers each being connected to said wall at the spaced ends of the arch and along one edge, the free edges of the louvers and the opposed edges of the wall defining an elongated opening through which the gases and sound waves may pass, the

size of the opening being determined by the extent to which the louvers are offset from the cylindrical wall.

3. A muflier comprising a shell having inlet and outlet openings in its ends through which gases and sound waves may pass while entering and leaving said shell, a domed partition in said shell including a cylindrical wall spaced from the wall of the shell, circumferentially spaced pairs of louvers in the cylindrical wall in the form of arches formed by deflecting portions of said wall inwardly, each pair of louvers being integral along one longitudinal edge with the cylindrical wall and being disposed angularly away from each other inwardly each to define with a louver of an adjacent pair opposed tangential openings to create a turbulence in the gases and sound waves passing therethrough.

4. A mufiler of the type described, in combination, a cylindrical shell having an opening at each end, a partition in said shell dividing the shell into two compartments, said partition including a perforate cylindrical wall spaced from the circumferential wall of said shell, and circumferentially inclined louvers shielding the perforation, said louvers being offset on the inside of said cylindrical wall and being arranged in pairs.

5. A muilier having a cylindrical shell closed at its ends and having an inlet opening in one end and an outlet opening in the other end, two oppositely facing substantially cup-shaped baffles, each including a perforate cylindrical portion concentric with the shell arranged in said shell, and a louver overlying the inside face of each perforation and spaced therefrom a predetermined distance to regulate the effective size of the perforations.

6. A muflier having a cylindrical shell closed at its ends and having an inlet opening in one end and an outlet opening in the other end, two longitudinally spaced cup-shaped bafiles extending in a common direction each including a perforate cylindrical portion concentric with the shell arranged in said shell, and a louver overlying the inside face of each perforation and spaced therefrom a predetermined distance to regulate the effective size of the perforations.

7. A muffler having a cylindrical shell including end walls, an inlet fitting in one end wall, and a plurality of ports in the other end wall, a substantially cup-shaped bafile including a perforate cylindrical portion concentric with and arranged in said shell, and louvers on the inside face of said cylindrical wall, one shielding each of the perforations therein.

JOSEPH P. MARX.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,184,431 Dodge May 23, 1916 1,213,558 Turner Jan. 23, 1917 1,833,256 Miner Nov. 24, 1931 1,842,921 Van Dyke Jan. 26, 1932 2,096,000 Miles Oct. 19, 1937 2,350,924 Rainville June 6, 1944 2,416,452 Marx Feb. 25, 1947 

